• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.5B
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• pp.925-930
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• 2000

The Problem of allocating paths is very significant in order to transmit a large amount of various data on the ATM network. Therefore, selecting an optimal path among available paths between the a source node and a target node has been researched. Alternate paths designed in previous PNNI routing is not considered on the group-occupation so that traffic congestion happens, when errors occur in the network which consists of a hierarchical network architecture extendable to a large network, We propose the Top-Down algorithm considering an average of the occupation among the groups reported from a leader node in each group and minimizing a traffic congestion

• Journal of the Korea Society of Computer and Information
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• v.9 no.3
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• pp.177-182
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• 2004

The existing group key management architectures applied to a small scale routing protocols may have many overheads with key distribution. Therefore this paper proposes a group key management protocol in PIM-SM multicast group communication. This method divide multicast groups with RP, and subgroup key managers are established in each RP and can be transmitted groups keys. And this does not have needs of the data translation and the new key distribution for path change. This does not have needs of the data translation and the new key distribution for path change, so the data transmission time can be reduced.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.4 no.3
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• pp.380-399
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• 2010

In this paper, we present a new class of attacks against an anonymous communication protocol, originally presented in ACNS 2008. The protocol itself was proposed as an improved version of ModOnions, which exploits universal re-encryption in order to avoid replay attacks. However, ModOnions allowed the detour attack, introduced by Danezis to re-route ModOnions to attackers in such a way that the entire path is revealed. The ACNS 2008 proposal addressed this by using a more complicated key management scheme. The revised protocol is immune to detour attacks. We show, however, that the ModOnion construction is highly malleable and this property can be exploited in order to redirect ModOnions. Our attacks require detailed probing and are less efficient than the detour attack, but they can nevertheless recover the full onion path while avoiding detection and investigation. Motivated by this, we present modifications to the ModOnion protocol that dramatically reduce the malleability of the encryption primitive. It addresses the class of attacks we present and it makes other attacks difficult to formulate.

• Journal of Korea Multimedia Society
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• v.7 no.10
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• pp.1421-1435
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• 2004

When various work was given from user, the existing mobile agent model migrated from node to node and process the work at the point that much traffics according to passive routing schedule are happened, until it makes service the work result, time cost of round work process for the distributed nodes are increased. Therefore, the existing agent systems need migration method to solve the problems of agent size increment or a lack of interoperability among agent systems. To solve these problems in this thesis, we design and implement an CORBA-based Mobile Agent Model(CMAM) for the efficient work process into the distributed nodes, when the mobile agents are migrated among the nodes, using an optimal path search by sensing of network traffic.

• Journal of Korea Multimedia Society
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• v.2 no.4
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• pp.451-458
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• 1999

This paper considers the problem of routing connections in multi-optical tree network using WDM (Wavelength Division Multiplexing), where each connection between a pair of nodes in the network is assigned a path through the network and a wavelength on that path, such that connections whose paths share a common link in the network are assigned different wavelengths. The problem of optimal colouring of paths on multi-optical network is NP-hard[1], but if that is the colouring of all paths, then there exists an efficient polynomial time algorithm. In this paper, using divided & conquer method we gave an efficient algorithm to assign wavelengths to the all paths of a tree network based on the theory of (7) and our time complexity $O(n^4log\; n)$.

• Journal of the Korea Computer Industry Society
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• v.8 no.4
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• pp.237-244
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• 2007

In this paper we investigate the benefits of a data aggregation to prolong the lifetime of wireless sensor networks. To reduce the overload of messages from source node to sink node, data aggregation technique is generally used at intermediate node in path. The DD-G(Directed Diffusion-Greedy) can diminish the consumption of node energy by establishing energy effective single path from source to destination. In this case, the nodes near sink node have some problems, i) overly concentration of energy consumption, ii) increase of message delay time. To solve these problems, we propose a new data aggregation method which consider distribution of network overload, especially at the nodes close to sink node. The result shows that it can save energy and network delay time.

• Journal of Communications and Networks
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• v.7 no.4
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• pp.509-524
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• 2005

Due to the strict requirements of emerging applications, per-flow admission control is gaining increasing importance. One way to implement per-flow admission control is using an on­path resource reservation protocol, where the admission decision is made hop-by-hop after a new flow request arrives at the network boundary. The next-steps in signaling (NSIS) working group of the Internet engineering task force (IETF) is standardising such an on-path signaling protocol. One of the reservation methods considered by NSIS is reduced-state mode, which, suiting the differentiated service (DiffServ) concept, only allows per-class states in interior nodes of a domain. Although there are clear benefits of not dealing with per-flow states in interior nodes-like scalability and low complexity-, without per-flow states the handling of re-routed flows, e.g., after a failure, is a demanding and highly non-trivial task. To be applied in carrier-grade networks, the protocol needs to be resilient in this situation. In this article, we will explain the consequences of a route failover to resource reservation protocols: Severe congestion and incorrect admission decisions due to outdated reservation states. We will set requirements that handling solutions need to fulfill, and we propose extensions to reduced-state protocols accordingly. We show with a set of simulated scenarios that with the given solutions reduced-state protocols can handle re-routed flows practically as fast and robust as stateful protocols.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.6
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• pp.528-534
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• 2013

The energy consumption problem should be taken into consideration in wireless sensor network. Many studies have been proposed to address the energy consumption and delay problem. In this paper, we propose BISA(Bio-inspired Scheduling Algorithm) to reduce the energy consumption and delay in wireless sensor networks based on biological system. BISA investigates energy-efficient routing path and minimizes the energy consumption and delay using multi-channel for data transmission by multiplexing data transmission path. Through simulation, we confirm that the proposed scheme guarantees the efficient energy consumption and delay requirement.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.87-89
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• 2002

This paper presents a new approach using an Improved branch exchange (IBE) technique to maximize the voltage stability as well as loss minimization in radial power systems. A suitable voltage stability index (VSI) for optimal routing algorithm is developed using novel methods both a critical transmission path based on a voltage phasor approach and an equivalent impedance method. Furthermore, the proposed algorithm can automatically detect the critical transmission path to be reached to a critical load faced with voltage collapse due to additional real or reactive leading. To develop an effective optimization technique, we also have applied a branch exchange algorithm based on a newly derived index of loss change. The proposed IBE algorithm for VSI maximization can effectively search the optimal topological structures of distribution feeders by changing the open/closed states of the sectionalizing and tie switches. The proposed algorithm has been tested with the various radial power systems to show its favorable performance.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.10
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• pp.130-137
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• 1990

The multipath multistage interconnection network is proposed which has the capability of dynamic rerouting. Construction of the network gets simpler, and the number of stages is reduced to $LOG_{2}$(N), so hardware complexity is reduced. This proposed algorithm makes it possible that destination adresses are used as routing tags, and it is easy to set up the path. Because this proposed network has a dynamic rerouting, backtracking is not necessary to set up another path when conflicts of switch faults are occurred. To estimate a performance, analytic methods are used and it is proved that probability of acceptance is improved in this Multipath MIN.